Drainage system



DRAINAGE SYSTEM Filed July 28. 1922 2 Sheets-Sheet 1 INVENTOR ATTORNEY wx M G. H. BARRUS Dec. 15, 1925- ,565. 72

DRAINAGE SYSTEM Filed July 28. 1922 2 Sheets-Sheet 2 Z6 1 L I l l l I KI l I K A ELSE 1 INVENTOR BY W M ATTORNEY i i anon-on a. mans, ornoszromnnssncnusnms.

"situation .m afimy as, semi to." 578,034.

To all whom it may concern.- a.

Be it known that I, Gnonor. H. Banana, a citizen of the United States,residing at Boston in the county of Suffolk, State of Massac usetts,haveinvented certain new and useful Improvements in Draina e Systerns;and I do hereby declare-the fo lowing.

., and has to do artlcularly with a system in which the individualheating units are revolving drying cylinders of the type com-,

monly employed in paper making machines, and the like. Morespecifically, the-invention contemplates certain improvements andmodifications in the structure disclosed in my United States Patent No.1,192,369.

In machines of this character each of the revolving drying cylinders iscommonly provided with ahollow bearing or trunnion through whichthesteam for heating the, drying surface of the cylinder is passed and alsothrough which the condensate is-withdrawn from the unit. Two types ofdrainage systems for removing the accumulated condensate from theinterior of the drying cylinders are in common use at present. In one ofthese systems, known as the bucket type, a plurality of scoops orbuckets are secured to the inner wall of the d ing cylinder so that atevery revolution .0 the; cyl

inder each bucket, during the lower ortion of its travel, takes up aquantit of t e condensed water and then empties it into a suitabletrough or discharge passage during the subsequent ortion of itsrotation. In the type of dralnagesystem known as the siphon system thedischarge passa e for conveying the condensate out of t e dryingcylinder assumes the form of a pipe enters ing the cylinder throughthehollow trunnion and thence extending downwardly within the cylinder sothat its open end is positioned a short distance from the cylindricalwall of the cylinder at its lowest point. This siphon'pipeis stationaryand water may accumulate within the cy inder until the open end of theipe is submerged. lVith this condition disc arge of the condensate willoccur-provided that sufiicient ressure difference exists between theinrior of the cylinder and the discharge mainqto produce allow throughthe siphon P he bucket stem of drainage has the advantage that't edischarge flow isnot dependent at low speedson the presence ofa certainressure difference between the interior o the cylinder and "thedischarge main. However, the efiectiveness of the bucket systemdecreases as the speed of the drying rollers is increased due to thefact ,that the water condensate tends to accumulate at the outer wallsof the cylinders under the action of the centrifugal force of rotation."As a result, even. with moderate cylinder speeds, the water is" held bythe ac t1on of centrifugal force in the buckets until the buckets areelevated, considerably above the axisof the cylinder. The time allowedfor the condensate to run out is thus materiall diminished and-, 'infact, this system of Y rainage may become entirely inoperative for highspeed machines such .as arecommonly employed in the manufacture of aper.

6n the-other hand, with the si hon system the pressure required within te drying cylinder to lift the water from the end of the siphon to thecenter of the hollow trunnion andestablish a lflow is often unavailableat the proper time and, as a result, water accumulates within the clinder to a considerable depth before a dlscharge flow is established.When the flow once starts it continues in considerable volume until thecylinder is em tied, whereupon the pressure within the cy inder isrelieved due to the fact that the water falls below the opening in thesiphon pipe and thus connects the interior of the cylinder directly withthe discharge main. It is readily seenthat the drainage with the siphonsystem is likely to occur in gulps, and that moreover during thatportion of the operation in which large quantities of water haveaccumulated within the cylinder the power required to turn the cylindersis greatly increased and the drying ca acity of the cylinders iscorrespondingly re uced. v

In neither. of the above typesof drainage is there any provision for thedischarge of Lil air which ma accumulate in the drying cylinders andecrease the heat transferring efficiency of'the drying surfaces.

One object of the invention is to prevent the accumulation ofcondensation water in the dryi-ng cylinder, and at the same timema1ntaining an adequate pressure difference between the interior of thecylinders and the drainage main so that'a continuous outflow of thecondensate will occur at alltimes. In this manner I reduce the amount ofcow densate present within the cylinders at any time to a minimum, whichquantity is determined by the distance of the opening at the inlet endof the siphon pipe from the adj acent portionof the cyhnder wall. Due tothe continuous character of the (discharge the level of thecondensate'is maintained at all times substantially flush with theopening in the siphon pipe and for this reason there is afi'orded ampleopportunity for the accumulated air within the cylinder, together with aportion of the'uncondensed steam, to enter the siphon pipe and beconducted out of the cylinder. I also provide means for maintainingwithin each cylinder a pressure sufficient to maintain a substan mittingonly condensed liquid to be dis-- tially continuous flow along thesiphon pipe and into the discharge mam.

It is also an object of the invention to provide a heating system ofthis type in which the uncondensed steam issuing from the dry-- ingcylinders may be efiiciently and conveniently separated from thecondensate in order that its available heat may be utilized in certainof the heating elements of the system, or in any other manner asdesired.

It is a further object to rovide a system of the above type in whic theapparatus provided for separating out uncondensed steam from the liquidcondensate and percharged from the system is inexpensive and ofrelatively small dimensions, so that the provision of a special pit orcompartment for housing this portion of the system is not required."

It is a still further object to provide in connection with the heatingsystem a single indicating element capable of registering thepressurejexisting in the various parts of the system so that properoperating conditions may be maintained, and to provide means by whichthe level of the condensate in the drainage system maybe determined inorder that suificient space may be allowed It is applicable 'to for theuncondensed vapor to flow and t separate out.

t is a still further object to provide a system of this type an im rovedelementof "simple, inexpensive an durable co'nstructionfor continuouslymamtaming a suflicient pressure difierence between the interior of eachdrying cylinder and the drain age main to' insure a continuous dischargefrom thecylinder;

In the accompanying drawin I have illustrated a. drying apparatus 05 therevolving cylinder type embodying my invention. The apparatus shown isof the type commonly employed in paper mills. In the said drawingsFigure 1 is a side elevational view showing the essential parts ofthesystem; Fig.2 is a partial vertical transverse view; Fig. 3 is a detailview of a modified portion of the system; Fig. 4 is a partial sideelevation, similar to Fig. 1, showinga somewhat modified system; and,Fig. 5 is a detail view of a portion of the apparatus. Referring to thedrawings, 1 indlcates a drying cylinder positioned at one end of anapparatus comprising a plurality of cylinders, the remaining dryingcylinders being indicated by the reference numeral 2. The cylinder 1 ispreferably located at the Wet or initial end of the apparatus, althoughthis arrangement is not essential to my invention. Each'of'the dryingcylinders is rotatably mounted upon the frame of the apparatus and isprovided with a hollow hearing or trunnion, as indicated at 3, and

through which extends the inlet and dis charge passages for the heatingmediumsupplied to the cylinders. Steam from any suitable source isfurnished to the supply main 4 and individual branch lines5communicating with the main 4 serve to supply The pipe 6 enters thecylinder through the I hollow trunnion 3 and has its portion within thecylinder bent downwardly so that the opening at the inner end ofthe piperests -a short distance above the lowermost point of the cylindricalwall of the drying element. The condensate entering the siphon pipe 6 isconveyed out of thecylinder through the hollow trunnion 3 and into themain returu' be established within the cylinder, which back pressurewill be sufiiciently .greatto -trate preferably, however, form therestricted pas-- establish and maintain a continuous flow through thesiphon pipe 6 and discharge line 8 into the main return header 7. Teconstricted portion 9 of the passa e .may simpl be a valve which ismaintaine partly close or ma be a gate valve in which .a notchis cut orthe purpose of'afiording a passa e of restricted cross section, asillusin 'my above-mentioned patent. I

sage 9 by means of a metallic disc having a centrally located orifice,as shown in detail in Fig. 9. This disc may be conveniently incorporatedinto the pipe line by inserting it at the junction between two lengthsof pipe, as shown, thecross section of the fluid passage at that pointbeing reduced in d1.

mension to the size of the orifice providedin the metal disc. A copperdisc provided with such orifice gives excellent service under theconditions met in systems of .this t pe It is readil seen that inasmuchas the flow through t e orifice'can occuronly at a given rate byproperly adjusting the dimensions of the orifice the pressure withineach drying cylinder may be raised suffi ciently above that of thereturn header to insure a continuous discharge flow. Under suchconditions the liquid level within the c linder will be maintained atsubstantially the level of theopen end of the siphon pipe 6, and notonly will the condensate be continuously withdrawn from the cylinder butalso a certain amount of the uncondensed steam together with the airaccumulating within the cylinder will be discharged. For the purpose ofprotecting the constricted portion 9 of the discharge assage frombecoming clogged by the gra ual accumulation of dirt, the orifice discis pref-. erably inserted in the line 8 at a poin'tjust below a bend inthe line, as shown at 10. The line 8 is extended somewhat past the elbow10, as indicated at 11, so that whatever impurities issue from thecylinder will tend to continue on and accumulate in the bcumulate in theupper portion of the header 7, at the same time moving along the length.

of the header in a direction the same as that in which the liquid isflowing. At the outlet end of the header 7 there is provided a loopcontaining two adjacent lengths of vertical piping 12 and 13. The liquidcondensate in the return header flows down into its lesser specificgravity, tends to continue on beyond the jIunction of the pipe 12 withthe header 7 hus an effective separation of. the vapor from the liquidis accomplished by the influence of gravity alone and the vapor passesup throu h the line 14 and serves as a heating me 'um for the dryingcylinder 1, after which it is dischar ed in the manner above describedthrough t e line 8? into the pipe 15 leadin to the hot well or otherplace ofdisposal or the liquid condensatej The vertical loop consistingprimarily of the lengths of piping 12 and 1-3 is rovided for the purposeof permitting only liquid condensate to pass into the line 15 leading tothe hot well, and to cause all the uncondensed vapor to pass up throughthe supply line 14 into the drying cylinder 1. In apparatus of this typeas sometimes'constructed the vertical arm 13 of the loop is madeappreciably lon erthan the arm 12 so that the additiona height of thewater column in the arm 13 will be sufiicient to compensate for theexcess, of pressure existing in the return header- 7 over that whichexists in' line 15 leading to the hot well. This type of constructionis, however, objectionable in that it is not'uncommon for the pipe 13constituting one side of the loop to reach a length as great as feet, orwhere both are of the samelength, to extend into the the vertical pipe12 wliile the vapor, due to ground that extreme distance. It is obviousthat the provision of a pit or other place of disposal for such agreatlength of vertical pipe results in a great deal of additional expense inthe installation of the apparatus. To overcome this difiiculty I haveconstricted a portion of the passage in thepipe 13 in such manner thatby means of a constriction ,a backpressure may be established upon theliquid endeavoring to flow up through the ipe 13 which pressure is theequivalent of that ordinarily supplied by the additional weight of thewater column provided in an elongated arm 13. This constricted passa mayconsist merely of a valve providedm the pipe 13, but for the purpose ofadjustment I preferably provide an open pipe 16 of cross section smallerthan that of the pipe 13 and discharging into the line 15 leading to thehot well. A certain constant portion of the condensate is thus free totake the shunt passage directly through the open pipe 16. A valve 17 isprovided in the line 13 above its juncture with line 16 and may beutilized when neccssary for the purpose of regulating the flow of thatportion of the condensate which is not accommodated by the pipe 16. Bythis construction the regulation affects only a fraction of the totalvolume of flow andmay thus be conducted with greater facility than wouldbe the case if the entire fluid stream were controlled by the regulatingvalve."

floor upon which the drainage system is mounted. The condensate willnormally stand at a level somewhere along the pipe 12, and this levelmay be varied byopening the valve 17 to a greater or lesser extent. Forthe purpose of determining approximately where the level of thecondensate in the p1pe 12 is located a series of testcocks 18 isprovided, the'upper'most of the cooks which discharges ,water upon Iopening indicating that the liquid level is somewhere between that cockand the one next above.

It may be noted that'the inner ends of the it is merely necessary toturn on the supply of steam to the main header 4, and the operation ofthe apparatus continues automatically. I have found that the copperdiscs containing the orifices may be continu-- ously used without thenecessity of varying the size of the orifice, and the proper,

size of orifice may be initially determined by experiment. terminationit will not subsequently be necessary to change the size of orifice'em-,ployed although such a change may readily be made merelyby substitutinga disc having a different sized-hole. I have found that the copper discscontaining the orifice are'more satisfactory than gate valves with anotch portion of the passage, inasmuch as valves are apt to be tamperedwith and the adjustment of the system thus disturbed. F urthermore, theprovision of the orifice discs affords a less expensive and a more rigidand less complicated structure.

For convenience in determining the pres sure in the various parts of thesystem, I provide a gauge 19 preferably capable of registering pressureseither above or below atmospheric, and arrangeconnections to the gaugeinsuch manner that the pressure at any part of the system may bedetermined. For instance, when the valve 20 in the gauge piping is openand the valves 21 and 22 are closed the gauge will register the pressurein the main steam header. \Vith valve. 21 open and the other valvesclosed the pressure indicated by the gauge is that in. the return .meansof an open After such initial deheader 7, while with valves 21"and 20both closed and valve 22 oplen the pressure in the line 15 leading tothe ot well is determined.

*In this manner it is possible to determine in a few .seconds whether.there is sufiicient pressure difference between the drying c l-' indersand the discharge main and whether there is the proper pressuredifference between the discharge main and the line 15 to secure a freeflow to the hot well.

In Fig. 3 I have illustrated a modification in which the vertical pipeloop is disgensed with. In this modification the conensate from thereturn header 7 flows down into the short vertical pipe'or chamber 23and is conveyed thence into the discharge' line 15 leading to the hotwell partly by pipe 24 and partly byv means of a trap 25. The largerroportion' of the condensate passes through pipe .24 35 whilethe trapserves to regulate the balance.v It is to be noted that this arrangementis more satisfactory than would be the case where the open line 24 isdispensed with and the trap employed alone, for the reason that in thearrangement shown the size of thetrap may be materially smaller and theexpense of the system correspondingly reduced. It may be of advantage tosubstitute the tra .25.and its associated pipe 24in place 0 the verticalloopwhen the s ace beneath the apparatus is particularly imited, as onlya small space is required to accommodate the, trap.,

In Fig.4 I have illustrated a 'further manner in whichthe steamrecovered from the return header 'Z'may be utilized. A heating employedto convey steam to any desired for the purpose of forming theconstricted,

po nt for utilization in whatever manner.- may be desirable, or thesteam may be partially 'usedto heat one of the drying cylinders andpartly for any other appropriate purpose. 1

I have described certain preferred embodiments of my invention, but itis possible that certain variations and changes may be made withoutexceeding the scope of the invention as defined in the claims. Forinstance, the cylinder 1 in which is utilized the steam recovered fromthe main return header need not be located in the position shown butmayv be any one of the heating elements of the systems. It is further tobe understood that while I have described my invention asemployed inconnection with a system of the type ordinarily employed in paper mills,it is equally applicable to any installation in which revolving dryingcylinders areemployed, such as thoseused in textile mills for dryingcloth, and the like.

I claim:

1. A system of the class described, comprising a plurality of dryingcylinders, means for supplying heating steam to said cylinders, meansfor removin the contents of said cylinders comprising a drainage mainand individual drainage connections between the respective cylinders andsaid main, and means for maintaining a continuous pres sure differencebetween the cylinders and said drainage main comprising a restrictedportion of constant area interposed in each of said individual drainageconnections.

2. A system of the class described comprising a drying cylinder, meansfor supplyin heating steam to said cylinder, means for e ecting adischarge from said cylinder comprising a drainage line and connectionfrom the cylinder to said line, and an obstruction in said connectioncontaining an orifice of fixed dimension whereby the flow through saidconnection is restricted and the pressure in said cylinder raised abovethat in said drainage line.

3. A system of the class described comprising a plurality of dryingcylinders, means for supplying heating steamto said cylinders, means foreffecting a discharge from said cylinders comprising a drainage main andindividual drainage" connections between the respective cylinders andsaid main, means for maintaining a continuous pressure differencebetween the cylinders and said drainage mainlcomprisin a metallic disccontaining an orifice of xed dimension whereby theflow through saiddrainage connections is restricted.

4. A system of the class described comprising a plurality of dryingcylinders, means for supplying heating steam to said cylinders, meansfor efiecting a discharge from said cylinders comprising .a drainagemain and individual drainage connections between the respectivecylinders and said main, means for maintaining a continuous pressuredifierence "between e cylinders and said drainage main, means for searat ing the condensate from the uncon ensed va or in saidlnaincomprising a passage for de ecting the condensate out of its previousdirection of flow and a separate assage for' receivin the vapor, andmeans or conveying sai uncondensed vapor to a point of utilization.

5. A system of the class described, c0mprising a plurality of dryingcylinders, means for supplying heating steam to said cylinders, meansfor removin the contents of said cylinderscomprising a raina e main andindividual draina e connections tween the respective cylin ers and saidmain, means for maintaining a continuous pressure difference between thecylinders and said drainage main, means for separating the condensatefrom the uncondensed vapor insald main comprising a downwardly extendingr passage for receiving the condensate, where by the condensate isdeflected by the action of gravity from its previous direction of flowand a separate passage for receiving the uncondensed vapor withoutaltering its age connections between the respective cylinders and saidmain, means for maintaining a continuous pressure difference between thecylindersand said main, means for separating the condensate from theuncondensed vapor in i saidmain comprising a passage for deflecting thecondensate out of its preplying said uncondensed vapor as heating mediumto the remaining cylinders.

' 1?. A system of the class described comprising a plurality of dryingcylinders, means for supplying .heating steam to a number of saidcylinders, means for removing the contents of said cylinders comprisinga drainage main and individual drainage connections between therespectivecylinders and said main, means for maintaining a continuouspressure difference between the cylinders and said main comprising arestricted portion of constant area interposedin each of said individualdrainage connections, a passage 'at substantially the outlet end of saiddrainage main for deflecting the condensate away from the uncondensedvapor, a passage for receivng the uncondensed vapor and conveying it"into the remaining drying cylinders as heating medium therefor, andmeans for effecting a continuous discharge therefrom.

8. A system of the class described comprising a plurality of dryingcylinders, means for supplying heating steam to said cylinders, meansfor effecting a discharge from said cylinders comprising a drainage mainand individual drainage connections between the respective cylinders andsaid main, a loop passage for. receiving and discharging the condensatefrom said drainage main, one branch of sad fluid conveying loop having aportion of restricted cross section for impedirig the flow of fluidtherethrough.

9. system of the class described comprising a plurality of dryingcylinders, means for supplying heating'steamto said cylinders, means foreffecting a discharge from said cylinders comprising a drainage main andindividual drainage connections between the respective cylinders andsaid main, 'a vertical fluid conveying loop for-revious direction offlow, and means for supceiving the condensate from said drainage main,the latter branch of said 100 being of restricted cross section forretar ing the flow of fluid therethrough, whereby a loop of maximumdimension comparable wit ceiling height may be employed to balance thepressure in said drainage maln. r 10. A system of the "class describedcomprising a plurality of drying cylinders, means l for supplyingheating steam to-said cylinders, means for effecting a discharge fromsaid cylinders comprising a drainage main and individual drainageconnections between the respective cylinders and said main, a looppassage for receiving and discharging the condensate from said drainagemain, the initial branch of said loop being of substantially uniformcross section and 'the latter branch of said loop having a portion ofrestricted cross section less than that of the unrestricted portion ofsaid latter branch, whereby a portion of the condensate is dischargedthrough said shunt passage and' the remainder through said restrictedportion, and means for varyin the fluid conveying capacity of saidrestricted portion.

I 11. A system of the class described comprising a plurality of. dryingcylinders, means for supplying heating steamto said cylinders, means forefi'ecting a discharge from said cylinders comprising a drainage mainand individual drainage connections between the respective cylinders andsaid main, a loop passage for receiving and discharging condensate fromsaid drainage main, the latter branch of said loop having a portion ofrestricted cross section for impeding the flow of fluid therethrough,and a plurality of test cocks provided on the initial branch of saidloop, whereby the approximate level of the condensate in said initialbranch may be determined.

12. A system of the class described, comprising a plurality of dryingcylinders, means for supplying heating steam to said cylinders, meansfor effecting a continuous discharge from said cylinders comprising adrainage main and individual drainage connections between saidrespective cylinders and said main, means for maintaining a continuouspressure difference between cylinders and said drainage main, comprisinga restricted portion of constant area interposed in each of saidindividual drainage connections, a loop passage for receiving anddischarging the condensate from said drainage main,- the initial branchof said loop being of substantially uniform cross section and the latterbranch of said loop havin a portion of restricted cross section, a s untpassage around said restricted portion of cross section less than thatof the unrestricted portion of said latter branch, whereby a portion ofthe condensate is discharged through said shunt passage and theremainder through the said restricted portion, and means for varying thefluid conveying capacity of said restricted portion.

A system of the class described, comprising a plurality of dryingcylinders, means for supplying heating steam to said cylinders, meansfor removing the contents of said cylinders comprising a drainage mainand individual drainage connections between the respective cylinders andsaid main, means for. maintaining a continuous pressure differencebetween the cylinders and said drainage main comprising a restrictedportion of constant area interposed in each of said individual drainageconnections, a pressure gauge, and connections whereby said pressuregauge may be caused to register the pressure within the dryingcylinders, in the drainage main, and in the discharge line,respectively.

In-testimony whereof I aifix my signature.

GEORGE H. BARRUS.

